Surface breaking and loosening machine



4 4 192 Oct 7 F. M. HARGRAVE SURFACE BREAKING AND LGOSENING MACHINE Filed Jan, 25, 1927 5 Sheets-Sheet l l ll ll lllnwun llm u m N R O T T. v

4 l Oct 7 F. M. HARGRAVE I SURFACE BREAKING AND LOOSENING MACHINE Filed Jan. 25, 1927 5 Sheets-Sheet 2 ATTORNEY;

Oct. 4, 1927. 1,644,582

F. M. HARGRAVE SURFACE BREAKING AND LOOSENING MACHINE Filed Jan. 25, 1927 I 5 Sheets-Sheet 3 ATTORNEY.

Oct. 4, 1927.

F. M. HARGRAVE SURFACE BREAKING AND LOOSENING MACHINE s Sheets-Sheet 4.

' Filed Jan. 25, 1927 O Y O n v I I I N j. [Wwgrauz INVENTOR.

v N M T A F. M. HARGRAVE SURFACE BREAKING AND 'LOOSENING MACHINE Filed Jan: 25, 1927" 5 Sheets-Sheet 5 ATTORNEY.

Patented @ct. a, 192.7, i

rnnn MERE-ILL naeefeavn, or cnna'n arres, Iowa.

BREAKING AND LOOSENING MACHINE.

Original application filed. September 15, 1925, Serial No. 56,508.

January 25, 1927.

This invention relates to road building machines more particularly to the surface breaking or loosening mechanism thereof, and is a division of my application filed September 15, 1925, Serial No. 56,508, and the invention has for its object, to provide in a manner as hereinafter setforth, a new and novel mechanism for shattering, breaking, hammering, chiselling, or loosening a road of its surfacing material thereof from the existing surface to a predetermined level and at a predetermined cross section of a street, roadway or pavement.

Further objects of the invention are to provide, in a manner as hereinafter set forth, a mechanism of the type referred to wh ch is comparatively simple in its construction and arrangement, strong, durable, thoroughly efficient in its use, conveniently adjusted, and comparatively inexpensive to set up.

With the foregoing and other objects in view, the invention consists of the novel construction, combination and arrangement of parts as hereinafter more specifically described, andillustrated in the accompanying drawings wherein is shown an embodiment of a mechanism for the purpose set forth, but it is to be understood that changes, variations and modifications can be resorted to which fall within the scope of the claims hereunto appended.

In the drawings wherein like reference characters denote corresponding parts throughout the several views Figure 1 is a top plan view of a mechanism, in accordance with this invention, for shattering, breaking, hammering, chlselhng or loosening a road or surfacing material thereof from the existing surface to a predetermined level and at a predetermined cross section of a street, roadway or pavement.

Figure 2 is a side elevation thereof.

Figure 3 is a section on line 33 Figure 1.

Figure 4 is a section on line 4 4L Figure 1.

Figures 5 and 6, are disassembled views in plan respectively of upper and lower frame plates for the mechanism and further showing the top and bottom guide plates associated with each of said frame plates.

Figure 7 is a section on line 77 Figure 4.

A mechanism, in accordance with this invention, is adapted to be carried by a mobile support including wheels and runners, of the type as diselesed in my applicationgeriai Divided and. Serial No. 163,497.

N 0. 56,508. The mobile support may be selfpropelled or operated as a trainer behind a tractor, truck or other motive power as referred to in my application Sr. No. 56,508.

The mobile support comprises a frame formed of anupper and a lower section referred to generally by the reference characters 1, 2 respectively. The section 1 isfarranged above the section 2, spaced therefrom and further projects forwardly thereof. As the upper section 1 of the mobile support, forms no part of the. surface breaking or loosening mechanism, as hereinafter set forth, said section 1 will not be specifically referred to, as full reference as to the arrangement, and construction of'the elements of section 1 will be found in my applica tion Sr. No. 56,508. As thelower section 2, other than the side members thereof, form no part of the mechanism as hereinafter set forth, the said lower section 2 will not be specifically referred to, as the construction this appliactiou filed and arrangement of the elements thereof are 7 specifically set forth in my application Sr.

N 0, 56,508. The side members of thelower section 2 are generally referred to by the referenee characters 8 and 4. The lower section 2 is of materially greater length than the upper section 1 and a surface breaking and loosening mechanism, in accordance with this invention, is carried by the lower sectlon 2 in proximity to the forward end thereof. The'fr'ont truck of the machine is generallyindicated at 5 and is carried by the upper section 1. The construction and ar rangement of the front truck 5 is fully referred to in my application No. 56,508 and as no claim is made herein to the construction and arrangement of such truck it is thought unnecessary to specifically describe the same herein. The surface breaking and loosening mechanism, in accordance with this invention, when mounted on the mobile support is spaced a substantial distance from the front truck 5.

It is the purpose of a breaking or loosening mechanism, in accordance with this in vention, by means of two batteries of vertically mounted hammers, drills, tampers, bars, chisels, or other similar devices. to shatter, break, hammer, chisel or loosen the road of its surfacingmaterial from the existing surface down to a pred i" sine-d level and at a predetermined cross s etion of the street, roadway or pavement. This mechanism may be operated simultaneously with other road building units and the theory of this operation is that when the speed of the machine over the surface is as designed and rated for a particular machine, the batteries of chisels or similar tools or instruments held firmly in a vertical position by guides will be moved upward against high tension spiral springs, either conical or helical, by a cam on a rotating cam shaft operated at a reasonably high speed, so that when each cam releases its chisel or similar tool, it will be forcibly propelled downward by the com- .bined forces of the spring and gravity until the lower end of the chisel or similar tool comes in contact with the pavement or roadway surface, or if the chisel is over a depression so that its end does not come in contact with said surface its force will be absorbed by a pair of resisting springs so designed as to slow up the chisel without damage or shock to the machine. The ma chine may have one,'two or more batteries of these chisels, each battery operating in sequence from end to end, so that only one chisel or tool strikes the ground at a time in each battery and only one cam is at its maximum load and position at one time. It is thought unnecessary to show a plurality of batteries, as the description of one will apply to the other and it is obvious that the operating means for the several batteries would be the same, so as to provide for the operating in proper sequence. By adjusting the spacing and number of the individual chisels, and batteries of chisels in accordancewith the proposed longitudinal speed in propelling the entire machine, substantially every square inch of road surface or pavement will receive at least one blow from the chisel or other tool. hen more than one battery of chisels or tools are used the cam shafts for propelling the said tools act together so that they operate at the same speed. The entire unit is propelled by a power unit or prime mover of a horse power in keeping with the size of the particular machine. The mechanism is adjustable vertically so that the depth to which the chisel or other tool may penetrate may be governed, and the force of the blow of any one unit may be varied by adjusting the elevation of a unit with relation to the surface under treatment.

The surface breaking or loosening mechanism in accordance with this invention, comprises a top frame plate 98 of rectangular contour having arranged at its longitudinal median a pair of oppositely extending rectangular projections 99, 100 at the end edges thereof and each of said projections is formed centrally with an opening 101 and further with pairs of openings 102. The forward side marginal portion of the plate 98 is formed with a series of transversely extending spaced slots 103 open the forward ends thereof. The slots 1023 provide clearances for the vertical movement of one set of tool forming elements of the mechanism and as illustrated the number of slots is eight, but this number can be increased or diminished, depending upon the number of tools forming the set. The rear side marginal portion of the plate 98 is formed with a series of transversely ext-ending spaced slots 104% open at the rear ends thereof. The slots 104 provide clearances for the vertical movement of another set of tool forming elements of the. mechanism. The number of slots 104 correspond with the number of slots 103. The slots 104; are staggered with respect to the slots 103. The slots 103 are spaced equi-distant apart with respect to each other and all the slots 104 with the exception of one, are spaced equi-distant apart, the slot spaced the greater distance is indi -ated at 105, and is one of the end slots of the series of slots. 7

Arranged below and spaced from the plate 98, is the bottom frame plate 106 and which is constructed in the same manner as the plate 98, with this exception that the plate 106 is not provided with the projections 99, 100. The forward set of slots formed in the plate 106 is indicated at 107, and the rear set of slots at 108. The slots 103 are arranged in vertical alignment with the slots 107 and the slots 107 and the slots 10% are arranged in vertical alignment with the slots 108.

Secured to the upper face of the plate 98 and extending across the set of slots 103 is a top drill guide and bracket plate 109, having its rear edge formed with spaced grooved notches 110 which constitute closures for the slots 103. The openings 111 are provided in the plates 98 and 109 for the passage of hold fast devices to secure the plates together. Mounted on the plate 98 and extending across the set of slots 104, which includes the slots 105, is a top drill guide and bracket plate 112 having its forward edge provided with notches 113 for closing the slots with which said plate 112 is associated. Openings 114 are provided in the plates 98 and 112 for the passage of holdfast devices to secure the plates together.

ill)

Mounted against the lower face of the open ends of the slots 108'. Openings are provided in the plates 106 and 118 for the passage of holdfast devices to connect the plates together. The plates 98, 109 and 112 are detachably connected together and this arrangement applies to the'plates 106, 115 and 118.

Arranged between the plates 98 and 106 and spaced between the longitudinal center and the side edges thereof is a pair of L beams 121, 122 having their flanges fixedly secured to the plates 98 and 106 by hold fast devices 123-. Openings 124 are provided in the plates 98 and 106 for the passage of the holdfast devices. The plates 109, 112, 115 and 118 are provided with sets of openings 125, 126, 127 and 128 respectively. The openings of the set 125 register with the slots 103. The openings in the set 126 register with the slots 104, which in cludes the slot 105. The open ngs 127 register with the slots 107 and the openings 128 register with the slots 108. Associated with each opening 125 and Formed in the plate 98 is a pair of openings 129. Associated with each opening 126 and formed in the plate 98 is a pa r of openings 130. Associated with each opening 127 and form-ed in the plate 106 is a pair of openings 131 and associated with each opening 128 formed in the plate 106 is a pair of openi gs 132.

When the plate 109 is secured in position, the openings 125 align with the openings 127 and the openings 129 align with the openings 131; When the plate 112 is secured in position the openings 126 align with the openings 128 and the openings align with the openings 132. The openings 125 and 127 are provided for the passage of bolts 133 which are connected with the plates 109 and 115 and extend through the slots 103 and 107. The openings 129 and 131 are provided for the passage of bolts 134 which are connected to the plates 98 and 106. The openings 126 and 128 are provided for the passage of bolts 135 which are connected to the plates 112 and 118 and extend through the slots 104 and 108; The openings 130 and 132 are provided forthe passage o'tbolts 136 which are connected to the plates 98 and 106.

A bolt 133, in connection with a pa r of bolts 134. or a bolt 135 in connection with a pair of bolts 136 confines between the plates 98 and 106 a compression spring 137 and a pair of butter springs 138., 138 which are arranged below the spring 137 and'separated therefrom by a split collar 139 clamped to a drill or other tool 140. Positioned against the upper and lower faces of said collar 139 are washers 141 and 142 respectively. The compression spring 137 is interposed between the plate 98 and the washer 141 and the buffer springsare interposed between the plate 106 and the washer 142. The

washer 141 provides in'eansforcompressing the spring 137 on the upward stroke of the tool and the washer 142 provides means for openings 145 in the plate 106, is an elevating block. As each of the elevating blocks are of the same construction, but one willlo'e described, as the description of one will a'pply to the other. The elevating blocks are oppositely disposed with respect to each other and each comprises an inner portion 146 and an outer portion 147 of less height than th former. The holdfa-st devices 148 engage in the inner portion 146 ofthe elevating block. The outer portion 147 is not only of loss height than the inner-portion 146, but of less length thanthe length of the I latter, and is centrally disposed with respect to the outer face of the inner portion 146.

he outer portion-147 is of the-same size as the projection 990i 100 fori'nedon the plate 98 and the projection is seated on the top of the outer portion 147, of the elevating block, as well as being secured therewith by hold- -fast devices 148' which extend through the openings- 102 in the projection. The outer part 147 is formed centrally with a vertically disposed opening 149 having the wall'sthereof threaded throughout and said opening 149 registers with the opening 101 in a projection 99 or 1.00. The threaded walls of the openings 149 of the'clevating blocks are engaged by threaded elements; capable when operated of vertically adjusting the elevating blocks for the purpose or el'evating and lowering the surface loosening niechan'sin Secured to the inner faceof each of the side members otthesec'tioi'i 2, is a combined support and bearing block 150, arranged in alignment with respect to the other. portion 147 01 an" elevating block,-- as well as below said portion 147, and said block 150 is provided Wltll a vertically disposed socket 151 opening in the top of the block.

Secured to the inner face of each of the side members of the section 2 of the frame v or the mobile support is a pair 01"- oppositely disposed vertically extending angle-shaped supporting members 152, 153, and between each pairof which is arranged a block 150,

and extending in each pair of supports'is the outer portion 147 of an elevating block,- and the SEtlCl pair of supports constitutes a uide tically disposed opening 155. through the opening 155 and through the for the part 147 during the vertical movement of the elevating block. The elevating blocks are simultaneously shifted and the means to provide for such operation will be presently referred to. Each pair of supports extend a substantial distance above the section 2 of the frame of the mobile support and between the upper ends of each pair of supports 152, 153 a bearing block 154 is fixedly secured. The block 154 has a ver- Extending opening 148 and into the socket 151 is an adjusting element for vertically moving an elevating block, and as each of the adjusting elements is of the same construction, but one will be described, as thedescription of one will apply to the other. Each of the ad justing elements is in the form of a vertically disposed shaft referred to generally by the reference character 156 and consisting of a plane lower terminal portion 157 engaging in the socket 151, a threaded intermediate multaneously elevating and lowering the ele vating blocks, each of the shafts 156, above a block 154, is provided wit-h a beveled pinion 163, meshing with a beveled pinion 164 carried on the rear end of a counter shaft 165. Secured to the upper end of the support 153 is a bearing bracket 166 for the rear end of the shaft 165. Arranged forwardly of the bracket 166 and secured to each side of the section 2 of the frame of the mobile support, is a vertically disposed standard 167, carrying a supporting bracket 168 at its upper end, and upon which is secured a bearing 169 for the forward end of the shaft 165, and the latter projects forwardly from the bearing 169 and carries a sprocket wheel 170. Connected to and operated by the sprocket wheels 170 is a transversely extending belt 171 of a link type. By the construction and arrangement '0. the parts as referred to, when either one of the shafts 156 is revolved, the bevel gear connection between the shafts will provide for the simultaneous operation thereof under such conditions vertically adjusting the elevating blocks.

Secured to the plate 98 in proximity to one end thereof is a transversely extending I-beam 172 and secured to the upper face of the plate 98, in proximity to the other end thereof is a transversely extending I-beam 173 of the same length as the I-beam 172. The securing means for each of said I-beams, consists of vertically disposed bolts 174, extending through the flanges of said beams, and also through the plate 98 and carrying on their lower ends securing nuts 175. Mounted on the top of the beam 172 is a pair of spaced bearings 176 and 177, which are 'iixcdly maintained in position by the bolts 174 which secure the beam 172 in position. Mounted on the top of the beam 173 is a pair of spaced bearings 178, 179 which are fixedly secured in position by bolts 174 employed for securing the beam 173 to the plate 98.

Arranged on the plate 98. in proximity to the I-beam 172, is a transversely extending, vertically disposed gear casing having its length the same as the width of the plate 98. The casing consists of a lower section 180, flanged as at 181, and extending through such flanges are holdfast devices 182 for fixedly securing the lower section 180 to the plate 98. The upper section of the casing is indicated at 183 and has its bottom flanged as at 184. The flanges of the section 184, seat on flanges 185 at the top of the section 180. Securing devices 186 are provided for detachably connecting the section together and which extend through the flanges 184 and 185. V

Journaled in the bearings 178 and 176 is a cam shaft 187, extending lengthwise of the plate 98 and further extending through the gear casing between its vertical center and one end thereof. Jour-naled in the bearing 177, 179 is a cam shaft 188 which extends lengthwise of the plate 98 and further through the gear casing at a point between its vertical center and the other end thereof. Fixed to the shaft 187 within the gear casing, is a gear wheel 189 and fixed to the shaft 188, within the gear casing, is a gear wheel 190 which meshes with the gear wheel 198. 188 together, through the medium of the gear wheels 189 and 190, provide for the operation of the shafts simultaneously in opposite directions with respect to each other. The shaft 187, as well' as the shaft 188, is provided with a set of cams corresponding in number to the number of drills or tools of a set. The cams of each set are so disposed as to operate the tools of a set with which they are associated in sequence, that is, one after the other. from one end to the other end of the set of drills or tools. The cams of the set carried by the shaft 187 are indicated at 191 and the cams of the set carried by the shaft 188 are indicated at 192. The cams of the shaft 187 are staggered with respect to the cam of the shaft 188. The shaft 187 carries a driven pulley 198, operated through the mediumof a belt transmission 194 from a drive pulley The connecting of the shafts 187 andv 195, carried by the shaft 196, of a motor 197, mounted on a support 198, secured to a pair of channel irons 199, which are fixedly connected to the sides of the section 2 of the frame of the mobile support. The shaft 196 provided with a wheel 200. The shaft 187 in proximity to the beam 173 carries a fly wheel 201 and the shaft 188, in

proximity to the beam 173 carries'afiy wheel 202 arranged in a position to clear the fly wheel 201. v p

Each of the tools of each set, comprises ashank 203 of a length to project above'the plate 98 and to depend below the plate 106, and at its lower end terminates in an enlarged beveled cutter 204. The upper end of the shank has a beveled head 205, carrying a right angularly disposed arm 206,

struck by a cam for the purpose of elevating the tool against the action of its spring 137, so that when the cam clears the arm 206 the force ofthe spring 137, will act, in connection with the weight of the tool to force fully propel the tool downwardly to act upon the pavement or roadway surface The tools of the set with which the cams 191 associate are indicated at 207, 208, 209, 210, 211, 212, 213, 214: and the arms of each of said tools at 215. The tools of the set with which the cams 192 associate are indicated at 2161, 217, 218,219, 220 221, 222, 223

and the arm of each of said tools at 224. The shanks of the tools 207 to 214 both inclusive extend through the slots 10% and 108. The shanks of tools 216 to 223 inclusive extend through the slots 103 and 107 The slots referred to are formed in the plates 98 and 106. Arranged over the plate 498, at the rear thereof,is apair of spacedvertically disposed supports 225, anchored in position through the median of a pair of angle pieces 26 .which are fixedlysecured to the plate 98. The tools 208 to 212 inclusive are positioned between said supports 225 and "secured toeach of said supports'225 1s a vertically disposed guide member 226. Ex-1 tending from one support 225 to the other is a pair of rods 227, 228, one arranged above the other, and both extending through the guide members 226, Carried by the rods 227 and'228 is a series of spaced anti-friction rollers 229 for the tools 208 to 212 inclusive; Mounted on the rods 227 and 228 are guide members 230 which aremain-tained in'spaced' 98, extend upwardly thereof, are'of yoke shapedcontour andassociate with the tools 207, 2'13and 214. i

The tools 217 to 223, both inclusive of the other set of'ltools, as wellasthe arms 22d of such tools, are guided in thesame manner as the tools208 to 212. The guide members are indicated at 233 and 234 and which are" constructed similar to the guide members 226 and 230 and supported in the same manner.

The anti fric'tion. rollers for the tools to 223 both inclusive are indicated at 235.

A yoke shaped guide bracket236is'securedto the plate 98 and associated with the 'too1 216."

The cams 191, when the-shaft 187 is op erated, engage under the arms 215 for the purpose of elevating the tools of that set with which said cams associate, and as before stated the arrangement of the cams 191 is such that the tools will operater'con'secu-f tively and the foregoing statement of opera tionapplie's to-the cams 192 wi-threspectto the tools of that set with which'thecams192 When the tools of both sets are associate. operated, thetool 207 operatedsimultaneously with and in a like manner "as the tool 216 and this statement applies to thet'ool's 20s and 217, 209 and 218,- 210 211M219, 211 and 220, 212 and 221, 213 and 222, and 214 and 223. i

he construction of the bottom of the tool may be varied to suit the class of surface un d r treatment, so that What is termed the surface loosening mechanism, may be employed as, a breaker for stone in macadam,

bituminous macadam, asphaltic or similar surfaces, or it maybe used as a ta'mp'erfto solidify any surface; or W1th mama-chine stationary it may be used to work its waydownw ard through a pavement or other suring or similar work.

face for the purpose of trenching, excavat The vertical adjusting of the surfa'ce loosening mechanism, from either side ofthe'machine, will cause said mechanismto remain" in the same relation to themobileflsuppoft constantly, or in other words, the axis o'f the meehamsm is parallel wrth the transverse axis of the mobile support. 7 f The mechanism as hereinbefore set forth face down to a predetermined level and at any predetermined cross section of the street, roadway or pavement, on the travel ofthe' and in accordance with this invention fpr 'o- 'vides means for shattering, breaking, hammering, chisellingor, loosening the road or its surfacing material from'the existing sup mobile support carrying said mechanismo'r when said mobile support is stationary, and 1 therefore it is thought that the manyadvan-f tages of a surface breal'iing and loosening mechanism, in accordance with this invention, can be readily understood'and although the preferred embodiment of the invention is as illustrated and described, yet it is to below a controlling spring in sequence, and-concentrically arranged bufi'er springs for each of said tools arranged below andin alignment with a controlling spring.

2. A mechanism for the purpose set forth comprising a set of vertically disposed sur- I face breaking tools, a cont'rolhng spring for each of said tools, a set of cam elements cooperating with said controlling springs for reciprocating said tools and further to provide for the operation of the tools of the set in sequence, concentrically arranged buffer springs for each of said tools arranged below and in alignment with a controlling spring, means carried by each of said tools for alternately compressing its controlling and buffer springs, each tool having means at its upper end struck by a' cam to shift it.

3. A mechanism for the purpose set forth comprising a set of vertically disposed surface breaking tools, each of the tools of said set having an angularly disposed portion at its upper terminus, a controlling spring for each of said tools, a set of cam elements arranged above and cooperating with said controlling springs and striking against said angularly disposed portions to provide for the reciprocation of the tools of the set, said cams disposed relatively to each other and to said angularly disposed portions to provide for the operation of the tools of a set in sequence, and concentrically arranged buffer sprin s for each of said tools arranged below and in alignment with a tool controlling spring,

4. A mechanism for the purpose set forth comprising a portable supporting structure, a vertically adjustable support arranged therein, connected therewith and provided atitstop with an upstanding set of spaced tool guides, a surface breaking tool extending through said support and each of said guides, controlling springs for said tools, a set of cams carried by said support, cooperating with said controlling springs and striking the tools directly for reciprocating these latter, and a series of pairs of concentrically arranged buffer springs arranged Withinsaid support and each air positioned or a tool and surrounding the latter.

5. A mechanism for the purpose set forth comprising a supporting structure, a vertically adjustable support arranged therein and provided at its top with an upstanding set of spaced tool guides, a surface breaking tool extending through said support andeach of said guides and provided at its upper end with an angularly disposed portion, controlling springs arranged within said. support for said tools, a set of cams mounted on said support cooperating with said controlling springs and striking the angularly disposed portions of the tools for reciproeating these latter, and a series of pairs of concentrically disposed buffer springs arranged within said support and each-positioned below and in alignment with a controlling spring and surrounding a tool, and means carried by the tools for alternately compressing the controlling and buffer sprlngs.

6. A mechanism for the purpose set forth comprising a supporting structure, a vertically adjustable support arranged therein and provided at its top with an upstanding set of spaced tool, guides, a set'of surface breaking tools extending through said support and said guides, controlling springs positioned on the support for said tools, a set of cams mounted on said support, cooperating with said controlling springs and directly striking the tools for reciprocating these latter, an operating shaft common to said set of cams and mounted on said support, said cams constructed and arranged to provide for the operation of the tools of the set in sequence from one end to the other end of said set of tools, and series of pairs of concentrically disposed buffer springs mounted in said support and each arranged below and in alignment with a controlling spring and surrounding a tool, and means carried by the tools for alternately compressing the controlling and buffer springs. I j

7 A mechanism for the purpose set forth comprising a supporting structure, a support arranged therein and provided with .a set of tool guides, a set of surface breaking tools extending through said guides and each hav ing its upper end provided with an angularly disposed portion, a controlling spring for. each of said tools and mounted onsaid support, a set of cams carried by the support, cooperating with said controlling springs and striking the angularly disposed portions of the tools for reciprocating these latter, an operating shaft common to said set of cams and arranged above said controlling. springs, said cams constructed and arranged to provide for the operation of the tools of the set in sequence from one end to the other end thereof, and buffer springs mounted in said support and each arranged below and in alignment with a controlling spring.

8. A mechanism for the purpose set forth comprising a supporting structure, a vertically adjustable support arranged therein connected therewith and provided with a set of tool guides, a surface breaking tool extending through each of said guides, controlling springs for said tools, a set of cams carried by said support, cooperating with said controlling springs and striking the tools directly for reciprocating these latter, said guides extending above said support and opposing the cams, a pair of adjusting devices for said support and providing the connection between the latter and said structure, and means for simultaneously operating said devices.

9. A mechanism for the purpose set forth comprising a supporting structure, a vertically adjustable support arranged therein connected therewith and provided with a set of tool guides, a surface breaking tool extending through each of said guides and provided at its upper terminus with a right angularly disposed portion controlling springs arranged within said support for said tools, a set of cams mounted on said support, cooperating with said controlling springs and striking the angularly disposed portions of the tools for reciprocating these latter, said guides extending above said support and opposing said cams, a pair of adjusting devices for said support and providing the connection between the latter and said structure, and means for simultaneously operating said devices.

10. A mechanism for the purpose set forth comprising two sets of surface breaking tools, said sets free of connection with each other, a controlling spring for each of said tools, two sets of cam elements cooperating with said controlling springs and striking directly with the upper portions of said tools for reciprocating these latter, a shaft common to each set of cams, a gear connection between said shafts to provide for the synchronous operation thereof, means for operating said gear connection, buffer springs each arranged below and in alignment with a controlling spring, a set of guides for each set of tools, a support common to said guides, tools, springs, cams and shafts, a supporting means, and adjusting devices for vertically shifting said support, said devices providing coupling means between said support and said supporting means whereby the former will be carried by the latter. 3

11(A mechanism for the purpose. set forth comprising two sets of surface breaking tools, said sets free of connection with each other, a controlling spring for each of said tools, two sets of cam elements cooperating with said controlling springs and striking directly with the upper portions of said tools for reciprocating these latter,

a shaft common to each set of cams, a gear connection between said shafts to provide for the synchronous operation thereof, means for, operating said gear connection, buffer. springs each arranged below and in alignment with a controlling spring, and each of said cams constructed and arranged with respect to its associated set of tools to provide for the operation of the tools of such set in sequence from one end to the other end of the set.

In testimony whereof, I aflix my signature hereto.

FRED MERRILL HARGRAVE. 

